Automatic pencil for drawing a line

ABSTRACT

An automatic pencil comprises a motor for constantly rotating the lead therein so that its point is automatically sharpened by contact with a writing surface.

United States Patent [191 Kunitoku Dec. 118 1973 [5 1 AUTOMATIC PENCILFOR DRAWING A 2.480,740 8/1949 Johnson 401 50 X LINE 75 Inventor:Sadayoshi Kunitoku, Oshima Arao, FOREIGN PATENTS OR APPUCATIONS ja a186,432 6/1907 Germany 401/50 1,394,248 2/1965 France 401/195 [73]Assignee: Nishitetsu Sangyo Co., Ltd.,

Fukuoka, Japan Primary ExaminerLawrence Charles [22] Flled' 1971Attorney-Holcombe, Wetherill & Brisebois [21] App1.No.: 169,369

[30] Foreign Application Priority [5 7] ABSTRACT Aug. 8, 1970 Japan..45/69553 An automatlc pencll comprises a motor for constantly rotatingthe lead therein so that its point is automati- CCll. Cally sharpened byContact with a writing Surface [58] Field of Search 401/50, 91 V 4Claims, 14 Drawing Figures [56] References Cited UNITED STATES PATENTS3,514,211 5/1970 Hasimoto et a1 401/91 X AUTOMATIC PENCIL FOR DRAWING ALINE SUMMARY OF THE INVENTION This invention relates to an automaticpencil for drawing a line In conventional automatic pencils, in order todraw a fine line, the tip of the lead must have been sharpened, orflattened like the head of a chisel, or the diameter of the lead must besmall. The former two methods, however, have the fault that since thetip of the lead gradually becomes round as it wears away, it isnecessary for the lead to be sharpened many times. And the latter methodhas the fault that thin lead under 0.3mm in diameter is apt to snap anda dark line cannot be drawn, even though it does not require sharpening.

My invention comprises means for drawing a fine clear line withoutsharpening the lead as long as the lead remains.

This invention will be better understood upon consideration of thefollowing detailed description of six embodiments thereof, withreference to the accompanying drawings, in which:

FIG. 1 is a schematic side view of the tip of the lead, illustrating thetheory of the automatic pencil for drawing a line;

FIG. 2 is a vertical section taken along the line II of FIG. 1;

FIG. 3-9 are axial sectional views showing various embodiments of adevice for holding a lead or turning it;

FIGS. 10-14 are transverse sections taken along the line 11-11 in FIG.3, the line Ill-III IN FIG. 4, the line IVIV in FIG. 5, the line V-V inFIG. 7, the line VI-VI in FIG. 9, respectively.

Referring now to FIGS. l-l4, the illustrated embodiments of theautomatic pencil for drawing a line according to this invention will nowbe described.

The automatic pencil in the present invention comprises a rod 2 foradvancing a lead in a holder 1, which rod is rotated by a small motor 3at one end of the pencil, e.g., a micromotor or a micro-airmotor. Thelead 5, which is mounted in a chuck 4 at the tip of the rod, rotateswith the rod.

In the present invention, if a new lead rotated by the small motor 3,the rod 2, and the chuck 4 is inclined at 30-45, the tip (a) of the lead5 wears to form a conical shape. The conical-shaped tip (a) of the lead5 continues to wear away due to abrasion on the paper 6, and the conicalshape is maintained until the lead 5 is used up. Then, theoretically, aline having no width ought to be drawn just under the axis of theconical-shaped top of the lead 5 by the base (p-q) of the tip (a) of thelead 5, if the lead 5 is hard and the paper 6 is quite hard and smooth.However since the surface of the paper is uneven, the line has a certainwidth. Nevertheless, the line is not more than 0.4 mm wide when a lead 2mm in diameter is used, and the line is not more than 0.2 mm wide incase of a lead 1 mm in diameter. (See FIG. 1 and FIG. 2; t, and t inFIG. 2 represent the width of the lines on the paper 6.)

According to the present invention, when the conical-shaped tip (a) ofthe rotating lead 5 is moved in one direction, while in contact with thepaper 6, a fine dark vantage that a dark line may be drawn with verylight pressure of the lead 5 against the paper 6 and, in addition, thewidth of the line can be freely controlled by pressure of the lead 5against the paper 6, or the quality of the paper.

Several specific embodiments of the present invention will now bedescribed in detail.

The first embodiment (illustrated in FIGS. I-3 and FIG. 10)

In FIG. 3, a holder 1 consists of two telescopic sec tions, with theleft section housing a narrow tube 8 and the right section housing amicromotor 3. When the right casing is pushed to the left the lead 5 isprojected from the narrow tube 8 by the rod 2, which is an extension ofthe drive shaft of the micromotor and carries a chuck 4 holding theinner end of the lead. The microairmotor 3 mounted rotates the rod 2 inthe center of the holder 1, thus rotating the lead 5 so that the tip ofthe lead 5, as shown in FIG. 1, becomes conical with a vertical angle of-90, if the holder is inclined at 3045 and the tip of the lead 5 rotatesin contact with the surface of a rough paper e.g. a sand paper, beforethe lead is actually used. Afterwards, when the base (p-q) of theconical-shaped tip (a) of the lead 5 moves along a ruler 7 in contactwith a paper 6, a line of the desired width (2 can be drawn on the paper6 by contact. The conical-shaped tip (a of the lead 5 is worn away dueto its rotation and thus maintains its conical shape. Therefore it isunnecessary for the tip of the lead 5 to be sharpened.

The second embodiment (illustrated in FIG. 4 and FIG. 1 1

In the second embodiment, a micromotor 3 is telescopically and axiallyinserted in the holder 1. One end of a rod 2 is connected to the driveshaft 9 of the micromotor by a coupling 10, and the end of a lead 5 isseated in a chuck 4 at the other end of the rod 2. In this embodiment,when the micromotor 3 is pushed to the left the lead 5 is projected fromthe narrow tube 8, since it is pushed out by the rod 2 connected to themicromotor 3.

The third embodiment (illustrated in FIG. 5 and FIG. 12)

In the third embodiment, a micromotor 3 is mounted near one end of aholder 1, a chuck 40 at one end of a rod 2 is located in the narrow tube8a near the tip of the holder 1, and in this embodiment, the part of alead 5 is inserted in the rod 12 and is gripped by the chuck 4a. Thetube 8a is slidable in the casing 1 against the resistance of thespring. When the narrow tube 8 is pushed to the right, the lead 5 isreleased by the chuck, which slides inwardly along the lead so that whenthe tube 8 is again permitted to move to the left, the lead projectstherefrom.

The fourth embodiment (illustrated in FIG. 6)

In the fourth embodiment, a push rod 14, one end of which projects fromthe end of the holder 1, is connected to a micromotor 3 in the holder 1.When the push rod 14 is pushed to the left and the micromotor 3 advancesin the direction of the narrow tube 8, the lead 5 is released by thechuck 4b and projects from the narrow tube.

The fifth embodiment (illustrated in FIG. 7 and FIG. 13)

In the fifth embodiment, the end of a rod 2, which has a chuck 4 at oneend for holding the lead, is inserted into a first tube 11 in which itis held by the second chuck 12. The end of said tube 11 is connected tothe drive shaft 9 of a small motor 3 through a shaft coupling l0, andthe end of a lead 5, which projects through a narrow tube 8 gripped bythe chuck 4. In this embodiment, when the micromotor is pushed to theleft, the rod 2 is released by the second chuck and the lead is pushedby the rod 2 to project it from the narrow tube 8.

The sixth embodiment (illustrated in FIG. 9 and FIG. 14)

In the sixth embodiment a micromotor 3 mounted in a holder 1 isconnected to a pressure tube 13 slidably mounted in the end of theholder 1. A rod 2 is connected directly to the drive shaft of the motor,and the end of a lead 5 in the narrow tube 8 is gripped in the chuck 4at the tip of the rod 2. In this embodiment, when the pressure tube 13is pushed to the left, the lead 5 is projected through the narrow tube 8by the rod 2.

The seventh embodiment (illustrated in FIG. 8)

In the seventh embodiment, a micromotor 3 is mounted at the end of aholder 1 and the lead 5 is gripped by a chuck 4 at the end of a rod 2extending from drive shaft of the micromotor. A narrow tube 8, thepartA, the part B and the part C are fixed to each other. Therefore, whenthe narrow tube 8 is pulled outwardly, all three of the parts connectedto it, A, B, and C move to the left together with it. After that, whenthe narrow tube 8 is returned to its original position, a desiredportion of the lead 5 projects outwardly through the narrow tube 8.

What is claimed is:

1. An automatic pencil for drawing a line comprising a hollow casinghaving an open end, gripping means rotatbly mounted in said casing inaxial alignment with said open end for holding a lead projecting throughsaid open end against transverse movement within said casing, and anelectric motor connected to rotate said gripping means and lead, bothsaid motor and gripping means being longitudinally sladable in saidcasing. slidable 2. An automatic pencil for drawing a line comprising ahollow casing having an open end, gripping means rotatably mounted insaid casing in axial alignment with said open end for holding a leadprojecting through said open end against transverse movement within saidcasing, and an electric motor connected to rotate said gripping meansand lead, said casing comprising two parts, one of which is slidablewith respect to the other, and said motor being fixed to one of saidparts.

3 An automatic pencil as claimed in claim 2 in which said gripping meansis a spring-operated chuck mounted to be opened when one part of saidcasing slides toward the other and closed when it slides away from theother.

4. An automatic pencil for drawing a line comprising a hollow casinghaving an open end, gripping means rotatably mounted in said casing inaxial alignment with said open end for holding a lead projecting throughsaid open end against transverse movement within said casing, and anelectric motor connected to rotate said gripping means and lead, saidmotor being mounted to slide in said casing and said gripping meansbeing a spring operated chuck mounted to be opened when said motorslides in one direction from a normal rest position and closed when saidmotor slides in the other direction and while it remains in said restposition, and said motor carrying abutment means positioned to advancesaid lead when said motor is moved in said one direction.

1. An automatic pencil for drawing a line comprising a hollow casinghaving an open end, gripping means rotatbly mounted in said casing inaxial alignment with said open end for holding a lead projecting throughsaid open end against transverse movement within said casing, and anelectric motor connected to rotate said gripping means and lead, bothsaid motor and gripping means being longitudinally sladable in saidcasing. slidable
 2. An automatic pencil for drawing a line comprising ahollow casing having an open end, gripping means rotatably mounted insaid casing in axial alignment with said open end for holding a leadprojecting through said open end against transverse movement within saidcasing, and an electric motor connected to rotate said gripping meansand lead, said casing comprising two parts, one of which is slidablewith respect to the other, and said motor being fixed to one of saidparts. 3 An automatic pencil as claimed in claim 2 in which saidgripping means is a spring-operated chuck mounted to be opened when onepart of said casing slides toward the other and closed when it slidesaway from the other.
 4. An automatic pencil for drawing a linecomprising a hollow casing having an open end, gripping means rotatablymounted in said casing in axial alignment with said open end for holdinga lead projecting through said open end against transverse movementwithin said casing, and an electric motor connected to rotate saidgripping means and lead, said motor being mounted to slide in saidcasing and said gripping means being a spring operated chuck mounted tobe opened when said motor slides in one direction from a normal restposition and closed when said motor slides in the other direction andwhile it remains in said rest position, and said motor carrying abutmentmeans positioned to advance said lead when said motor is moved in saidone direction.